Base Projects (Part II)

One disadvantage of using 3rd party components from a tutorial perspective is that we need to carefully configure our build system to find the libraries. We may also need to copy library files (.dlls) or resources into specific in order that they can be used. You may have already encountered this in the first year with SDL/SDL2 or with OpenGL in Real-time Graphics. We're going to use CMake to get around both these problems an allow us to work anywhere by simply cloning our project and re-running cmake to generate our build environment.

Overview

The process:

1. Create a fork of the project on Bitbucket.
2. Clone the base project.
3. Create a build directory.
4. Run CMake
5. Build
6. Install
7. Run/Debug

We started with a base project which included Ogre now we're adding bullet Bullet.

Bullet Base Project

The Ogre with Bullet Base Project is here. Again I'm hoping to add branches from this master project which provide examples for collision detection, ray tracing etc.

Creating a Fork

Though the Bitbucket Dashboard create a fork of the above repository, the fork option is not obvious. You'll click the + and select Fork the rest of the process is just like creating a new repository (and should be familiar).

Clone the Base Project

Make sure you in the directory you want to store you're working version of the project. Open GitBash and use this to clone your repository.

> git clone ...

Create a Build Directory

In explorer navigate to the directory into which you've cloned your project and inside the o3d_1-14_bull_3_base directory create a build directory.

Run CMake

We'll use the CMake-Gui (as we have for Ogre and Bullet), the makes configuring CMake to find Ogre much easier. Make sure you have Grouped checked!

Here's the options to change, I've included the full list at the end but hopefully you won't need it!

The image above shows my configuration for the base project. Set the OGRE_DIR to the SDK path, this should be <where you cloned>/ogre/build/sdk/CMake your path will start differently to mine but should end the same unless you changed the SDK output directory when configuring Ogre.

BULLET_ROOT

BULLET_ROOT is not an existing parameter, its an optional one used if bullet is not installed in a standard location. We'll be setting bullet root to the sdk directory we created as an output directory when we compiled bullet. To do this we click Add Entry, this brings up a dialogue asking for the name, type and value.

Name: BULLET_ROOT

Type: Path

Value: <path-to-bullet>/bullet/build/sdk

Configure CMake and Generate the a Visual Studio project.

Build

Change the start up project to SimpleGame, then Build the project (select Build from the Build menu).

Install

You will need to build the install target, this is not a real target but runs a build script. This copies the executable and the required configuration files, link libraries etc. to a sub-location in the build library.

Ogre3d relies on a number of config files and media files being present. To ease development placed these in a directory called dist the install step copies these into the build directory and place it with the executable. You may note that there is no .dll for Bullet, this is correct. Bullet is a static library so when it is linked against our game it is built into the executable.

You should have the following file structure:

dist
├── bin
│   ├── resources.cfg
│   └── SimpleGame
└── media
    ├── materials
    │   ├── scripts
    │   │   ├── Examples.material
    │   │   └── Ogre.material
    │   └── textures
    │       ├── GreenSkin.jpg
    │       ├── nskingr.jpg
    │       ├── rockwall.tga
    │       ├── spheremap.png
    │       └── tusk.jpg
    ├── models
    │   ├── cube.mesh
    │   ├── ninja.mesh
    │   ├── ninja.skeleton
    │   └── ogrehead.mesh
    └── packs
        └── SdkTrays.zip

The media directories are mostly for later tutorials which require loaded models. Packs are actually zip files as Ogre supports the loading of resources from one or more archives.

Run / Debug

CMake can set custom properties on different operating systems, in the case of Windows I've set a variable used by Visual Studio to identify its runtime library. As a result it should be possible to just run/debug as normal.

For Debugging Only

Here are all the other options, there should only be two we need to set. But I'm proving a full list in case you need to double check your setup. I've made the ones we set bold, with these set CMake should be able to populate the rest.

BULLET Group of Options

CMAKE Group of Options

Ogre Group